DeSean Jackson and Jeremy Maclin have spent their careers playing under the same head coach, offensive coordinator, and position coach. They have started together for four seasons, but the offense they're learning now under coach Chip Kelly is considerably different from what they've done in the past.

Among the changes: how they receive the play and how they run their routes. Instead of going to the huddle to hear the play from the quarterback, they get directions signaled from the sideline. The routes they run are different, and so are the options they have as they go through a particular route.

"I think that's the freedom that we're capable to have out there," Jackson said. "Depending on the defense, if the defender's way back, if we can beat them on the go, then that's the point. But if not, we're able to still, within the route, have the option to stop if the cornerback is bailing for his life to not get beat deep. So it's really a win for the receiver. Going out there, it's like you have a double route."

This is flexibility that Jackson said he never had in the past, when he needed to run a designated route. The new approach also requires the receivers to learn each pass-catcher's position on the field, because they could be lined up in any one of them on a given play.

"It's definitely tough, honestly, because I've never had to learn everybody's position," Jackson said. "I only really had to know one position, which was the 'Z' wide receiver. Now it's like I'm learning the 'X,' the 'A,' the 'Y,' and really just knowing the concepts of the offense. Right now, it's at a very comfortable level where I'm able to go out there and see the signals and go out there and get my job done."

Maclin said the same routes that the receivers ran last year are still there but that there are "different ways to do it."

The Eagles need the change to benefit both receivers. They are expected to be blue-chip players. Jackson, 26, was a 2008 second-round pick and is a two-time Pro Bowler. Maclin, 25, was a 2009 first-round pick who had more catches in his first four seasons than any receiver in franchise history, but he has yet to have a 1,000-yard season.

Both have displayed flashes of excellence with occasions of inconsistency. Their futures in Philadelphia are both promising and uncertain. Maclin is a free agent at the end of this season, while Jackson has little guaranteed money on his five-year contract beyond this season.